How to Tell When Homemade Toffee Is Ready

What it means

• The hard-crack stage is 300-310F (149-154C), the point at which cooled sugar syrup is hard and brittle rather than chewy.
• Color is a key cue: properly cooked toffee is a rich amber, roughly the shade of a copper penny or peanut butter.
• The cold-water test confirms doneness when a bit of syrup dropped into ice water sets into threads that crack cleanly.

Action steps

1. Clip a candy thermometer to the pan and cook to 300-310F (149-154C).
2. Watch the color shift from pale gold to deep amber as it nears the target.
3. If you have no thermometer, drop a little syrup into a glass of very cold water; ready toffee forms brittle threads that snap.
4. Pour it out immediately once it is ready, since carryover heat can push it toward burnt.

Risks & deadlines

• Pulling it too early (below about 290F) leaves toffee soft, chewy, or unable to set; going past about 310F makes it taste burnt and bitter.